Dredge



NOV. 8, 1932. w MAC'AULAY I 1,887,101

DREDGE Filed Aug. 2. 1930 3 Sheets-Sheet 1 INVENTOR. Wo/zer A7 Macau/agA TTORNEYS.

Nov. 8, 1932. w. B. MACAULAY ,8

' DREDGE Filed Aug. 2. 1930 3 Sheets-Sheet 2 IN V EN TOR.

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Nov. 8, 1932.

W. B. MACAULAY DREDGE 5 Sheets-Sheet 3 Filed Aug. 2. 1950 U, 0 mm n 7 Zr W.. B h

Patented Nov. 8, 1932 UNITE-DTYV'ST'ATES' PATIENT" oFF1cE WALTER BMAOAULAY, F OAKLAND, CALIFORNIA, ASSIGNOR TO YUBA. MANUFAC- TUBINGCOMPANY, or

1 01mm 1 1 I SAN FRANCISCO, CALIFORNIA, CORPORATION OF CALI- mannerApplication flled Au gust 2, 1930; Serial No. 472,562.

My invention relates to bucket .dredges especially of the type providedwith a digging ladder and a conveyor. 7

It is customary in the use of such dredges to float them on a body ofWater either natural or artificial and to lower the digging ladder belowthe surface of the water and against the material to bedredged. A lineof buckets on the ladder is operated to convey the material 0 throughthe water and above the level of the water to discharge onto the bargeportion of the dredge. Dredges of this character are usually ofconsiderable size and the ladder which supports the entire line ofbuckets is relatively large and massive. I, Necessarily therefore theauxiliary construction for supporting and maneuvering the ladder is ofrelatively great size and weight. In the past considerable difficultyhas been encountered dredged when carried by the buckets along the upperside of the ladder is prone to spill over and discharge onto the ladderitself. Although some of'such discharged material falls clear of theladder and some additional portion eventually is dislodged,nevertheless, a considerable amount of such material remains on theladder. The material thus deposited not only increases the weight of theladder tremendously thereby necessitating extra strong construction andsupport but also in numerous instances interferes with any auxilarymechanism which may be supported on the ladder, such as for instance,rollers for supporting the upper run of the line of buckets. Attemptshave heretofore been made to discharge such accumulated material bymeans of a stream of water flowing from 40 the upper end of the inclinedladder toward the lower end to efl ect a sluicing action. This expedientis effective on the upper portion of the ladder but is absolutelyineffective forthe lower or immersed portion of the ladder inasmuch'asthe water used for sluicing together with the material carried away by.it is dissipated immediately upon merging with the water upon which thedredge is floating.

It'is therefore an object of my invention to provide a means forpreventing undue accumulation of materialflon a dredge ladder.

due to the fact that ,the material being.

Another object of my invention fis to provide a construction for adredge ladder which is comparatively light in weight.

, The foregoing and I other objects are attained in the embodiment ofthe invention as shown in the drawings, in which Figure 1 is asimplified showing of the forward portion of a dredge embodying a ladderconstructed in accordance with my invention.

Figure 2 is a side elevation to an enlarged scale of the upper portionof a ladder in ac cordance with my invention.

Figure 3 is a side elevation tothe same scale as Figure 2 of the lowerportion of a 'dredgeladder' in accordance with my inven dredge'ladder ofmy invention.

' Figure 9 is a diagrammatic plan of the con-' trolling lines for adredge ladder..

Figure 10 is similar to Figure 9 but discloses a modified form ofcontrol lines fora dredge ladder.

In its preferred form, the dredge of my invention includes a laddercomprising a pair of side plates joined intermediate their ends by aplurality of diaphragms which present a minimum obstruction to materialdischarging from the bucket lines encompassing the ladder and the ladderis further provided with a deflector adjacent the lower or immersed endthereof for directing the flow of discharged material.

In the form of my invention shown herein there is provided a dredge,generally designated 6. At its forward endof the dredge is provided witha boom or gantry 7 which is re tained in place by suitable tackle 8anchored to the dredge frame 9. Suspended from the outer end of thegantry 7 is additional tackle 11 adapted normally to extend below thesurface of the water, indicated at 12, to support the lower, immersed.end of a ladder 13. The upper end of the ladder is carried 011 a shaft1d mounted in the dredge frame 9. By suitably operating the tackle 11the lower end of the ladder 13 can be raised and lowered into and out ofthe water to control the point at which the dredging operation occurs.The

ladder usually is operated about in the posi tion shown in Figure 1 at aconsiderable inclination to the horizonta Lateral movement of the ladderand of the forward end of the dredge is controlled by'lines running oversheaves and located by stationary piles 15 according to either of theschemes shown in Fi ures 9 and 10.

t the lower end of the ladder 13 is disposed a tumbler 16 about whichpasses a conveyor 17 including a line of buckets 18. The upper run 19 ofthe line of buckets follows closely the upper edge of the ladder 13 andpasses about an upper tumbler 20 on the shaft 1 1. Thelower or returnrun 21 of the conveyor follows for a distance the lower edge of theladder 13 and then depends there-from in a curve to return to the lowertumbler 16 and repeats the circuit. The conveyor or line of buckets thusencompasses the ladder 13. V In constructing the ladder 13 I preferablyprovide a pair of side plates 22 and 23 which are substantiallyco-extensive and are disposed in parallel relationship. The plates eX-tend substantially from the upper tumbler 20 to the lower tumbler 16 toprovide a pair of parallel beams. In practice the side plates arepreferably fabricated of a plurality of smaller platesections but ineffect they are continuous and I therefore refer to them in the claimsas side plates. These plates 22 and 23 are preferably reinforced alongtheir edges with suitable angles such as 24 and are in general providedwith the usual structural features The upper edges of the side plates 22and 23 are customarily provided with a series of spaced rollers 26adapted to support the upper run 19 of the line of buckets.

The upper portion of the ladder 13 as particularly shown in Figure 2, isprovided between the side plates 22 and 23 with a top plate 27 disposedslightly below the upper bounding edge of the side plates and eXtend ingparallel to the upper surface thereof. Material which is discharged fromthe buckets 17 adjacent the upper portion of the ladder 13 is depositedon the top plate 27 and is sluiced therefrom by a stream of waterplaying upon the upper end of the top plate. The top plate prefeablyextends along the 1 adder 13 to a point adjacent the water line or thepoint of immersion of the ladder. The

sluicing action is therefore effective on the upper portion of theladder to remove any deposited material and dissipate it into the bodyof water.

In order, however, to maintain the ladder 13 free from depositedmaterial below the water line where its weight is particularlyobjectionable and where unsuccessful attempts have been made in the pastto prevent the deposit of extraneous material, I preferably interruptthe top plate 27 and interposc between the side plates 22 and 23 aplurality of dialilhragms 31 which preferably are metal plates spanningthe side plates 22 and 23 and secured thereto by any suitable means andadditionally held by angles 32. The diaphragms 31 are preferably locatedin the ladder 13 at a considerable inclination with respect to the upperbounding edge of the side plates 22 and23 so that the diapnragms e2;-tend substantially vertically when the ladder 13 isin a digging positionas is disclosed in Figure 1. The diaphragms 31 thus present a minimumobstruction to the discharge of material falling from the line ofbuckets 17 and permit the material to fall gravitational.- ly throughthe water and pass the lower line of buckets 17 to deposit on thebottomof the body of water. relatively quite thin they present 0111 a verysmall area upon which material can lodge and therefore insure that theweight of the ladder will be increased only an insignificant percentageby the interception of such discharging material.

Although the diaphragms 31 are quite effective for their purpose it isin practice difficult to continue their use to the extreme lowor end ofthe ladder 13 because of the strong bracing necessary for the lowertumbler 16 and the additional reinforcement required by the ladder atthis point. I therefore construct the ladder particularly as shown inFigures 3 and 4c. The diaphragms 31 are not used in close proximity tothe lower end but I preferably span the side plates 22 and 23 with adeflector 33 which is preferably a metal sheet of inverted V crosssection located adjacent the upper bounding edges of the side plates 22and 23 and extending from the lowermost diaphragm 31 approximately tothe tumbler 16. The angle of the deflector 33 is such that the path ofmaterial falling into the buckets passes over the deflector withoutlodging thereon. That is, the effective angle of the deflector is theangle that the path of a piece of material falling over the deflectormakes with the horizontal. It is the resultant of the angle of theladder 13 with respect to the horizontal and the angle of inclination ofthe deflector 33 with the ladder 13. The angle referred to is preferablygreater than the angle of repose of any material discharged by thebucket which, therefore, is directed away from the ladder 13 to fall tothe bottom of the body of water.

In accordance with my invention there is provided a means for preventingundue accumulation of deposited material on the lad- Since the diaehrams 31 are der of the dredge thereby enabling the designer to constructthe ladder without regard to excessive overloads by virtue of depositedmaterial and to provide a structural arrangement which is not only amplystrong but is extraordinarily light for this class of service.Furthermore, there is provided not only a way of offering practically noobstruction to material adjacent the central portion of the ladder butthere is also afforded a way of dissipating material which ordinarilywould deposit adjacent the lower end of the ladder and near the lowertumbler.

I claim:

1. A dredge comprising a ladder, side plates on said ladder, anddiaphragms spanning said plates and inclined to the longitudinal axis ofsaid ladder.

2. A dredge comprising a ladder, side plates on said ladder, diaphragmsspanning.

said plates and inclined to the longitudinal axis of said ladder, and adeflector spanning said plates between their upper edgesand adjacent tosaid diaphragms.

3. A dredge comprising a ladder having a longitudinal axis, parallelside plates on said ladder, a deflector spanning said plates adjacentone end of said ladder, and diaphragms inclined to said axis andspanning said plates between the ends of said ladder.

4. A dredge comprising a ladder adapted to be disposed normally at aninclination to the horizontal, parallel side plates on said ladder, anddiaphragms spanning said side plates and adapted to be disposed normallysubstantially vertically.

5. A dredge comprising a ladder including a pair of coextensive,parallel side plates, an inverted V-shaped deflector fastened to theupper edges of said plates adjacent one end thereof, and a plurality ofdiaphragms fastened to and extending between said plates, saiddiaphragms being materially inclined to the bounding edges of saidplates.

6. A dredge comprising a ladder havin a longitudinal axis, side plateson said ladder, and diaphragms spanning said plates, said diaphragmsbeing inclined to said axis and defining substantially uniform passagesvertically through said ladder.

In testimony whereof, I have hereunto set my hand.

- WALTER B. MAOAULAY.

